CUMMING, Ga. (AP) — Newt Gingrich Saturday blamed negative ads run by Mitt Romney and an allied independent group — not dissatisfaction with the Republican field — for depressing voter enthusiasm and turnout in the Republican presidential contest.

The former House speaker made his remarks at a campaign stop in Georgia, which holds its primary on March 6, Super Tuesday. Gingrich represented the state's 6th congressional district for 20 years and is yoking his hopes for a campaign comeback to winning his former home state.

"It all hinges on Georgia," Gingrich told an audience in Suwanee, saying victory in the state would serve as a springboard for racking up additional wins across the country. He later clarified his remark, saying he thought he had a good chance to win Georgia but it wouldn't determine the fate of his candidacy.

"There are no slam dunk states," Gingrich said.

Herman Cain, the former pizza executive from Georgia who dropped out of the presidential contest in December and has endorsed Gingrich, introduced him at campaign stops in suburban Atlanta.

While Gingrich insists he's running a positive campaign focused on issues, he criticized Romney repeatedly for running attack ads — "negative junk" as Gingrich called them — which Gingrich said had demeaned the contest and turned off voters.

"It drove down participation," Gingrich said. "We have a target, it's called Barack Obama. The Romney people don't seem to get that."

Cain concurred, adding, "All the negative stuff is starting to wear thin on people. The only thing it's done is bring down participation."

Restore Our Future, a pro-Romney super PAC run by advisers to the former Massachusetts governor, has spent about $30 million on ads in the campaign, with most so far targeting Gingrich. The group's ferocious ad campaign helped topple Gingrich's chances in Iowa and flattened him in Florida.

It's true that Republican turnout has dropped in almost every state contest compared to four years ago despite a fierce desire among GOP voters to unseat Obama. South Carolina, which Gingrich won, is the only state to have seen a spike in turnout so far.

Gingrich has taken credit for the increased turnout in South Carolina, saying it showed the effectiveness of his ideas. But plenty of negative ads ran there as well, including a $1.6 million ad from a pro-Gingrich super PAC, Winning Our Future, which highlighted Romney's shifting position on abortion.

Restore Our Future is spending roughly $6 million on TV ads in Michigan and Arizona, which hold primaries Feb. 28; Georgia and other Super Tuesday states including Oklahoma, Tennessee and Ohio; and in Mississippi and Alabama, which vote March 13.